We have determined that a significant portion of elderly nursing home residents with a history of multiple falls have severe, quantifiable abnormalities of both gait and balance. Using a simple quantitative test of balance (the Postural Stress Test), in conjunction with more comprehensive testing on a balance platform, as well as a quantitative gait analysis as predictors, we propose to perform a 4 year longitudinal study in 1,300 residents of health related facilities to determine our ability to predict the occurrence of falls in the future as well as describing the natural history of elderly fallers. In those individuals with a history of falls, we have already demonstrated: impaired power especially in the ankle dorsiflexors, diminished lower extremity tactile-vibratory and proprioception function and CT abnormalities (hypodensity) in the hemispheric white matter. Using a cohort of 120 fallers and controls from the longitudinal study, in a case control format, we will determine the physiologic substrates of falling. This will be accomplished by relating the above abnormalities of gait and balance to measures of sensory and motor dysfunction, and ultimately, to lesions and/or disease of the nervous system. The predictive tests of falling and description of the sensorimotor dysfunction underlying falls will be readily applicable to improving our therapeutic approach to falling.